This invention relates to 1,4-disubstituted piperazine compounds useful as medicines, their production and use. More specifically, the present invention relates to compounds represented by the formula: ##STR2## wherein A stands for a condensed polycyclic hydrocarbon group, R stands for a phenyl group substituted with a lower alkoxy group, X stands for a methylene group, carbonyl group or thiocarbonyl group, and m denotes 2 or 3 and their salts, which are useful as platelet activating factor (PAF) antagonists.
PAF has a phospholipid structure and is a chemical transmitter existing in a living body. It has been made clear that PAF is, in a living body, closely concerned with allergy, anaphylaxis, inflammation, etx. and it has also been known that PAF has a strong hypotensive activity and platelet agglutinating activity. On administering PAF to an animal, the animal may in some cases be killed from shock. Symptoms caused by the shock from PAF have much resemblance to those caused by the shock from endotoxin, and it has been considered that PAF is concerned with the endotoxin shock.
On the other hand, while a variety of compounds having PAF-antagonistic activity have been known, very few of them are satisfactory in PAF-antagonistic activity in a living body. And, even when then PAF-antagonistic activity in a living body is satisfactory, not a few of those compounds have some restrictions in the administration method.